Inflatable mattress and pressure system



Aug. 26,1969 J. K, WHITNEY INFLATABLE MATTRESS AND PRESSURE SYSTEM 3Sheets-Sheet 1 Filed Feb; 25, 1966 Aug.v 26,v 1969 J K WHWNEY 3,462,178

` INFLATABLE MATTRESS AND PRESSURE SYSTEM Filed Feb. 25', 1966' 5sheets-sheet 2 IN VEN TOR. @HN K. WHITNEY BY HM ATTORNEY Aug. 26, 1969J, K. WHITNEY 3,462,778

v INFLATABLE MATTRESS AND PRESSURE SYSTEM Filed Feb. 25. 1966 '-5sheets-sheet s 160 .fao 20o 22o 240 26o fao ab 32o 340360 #om z-i-#ULD-bm Y MwST--v Y k--mw--m /NPUT 1N VENTOR. JoH/v K. WH/TNEY B Y@MQ/ff ATmRNfY United States Patent O 3,462,778 INFLATABLE MATTRESS ANDPRESSURE SYSTEM Iohn K. Whitney, Orchard Park, N .Y., assignor to GaymarIndustries Inc., a corporation of New York Filed Feb. 25, 1966, Ser. No.530,164 Int. Cl. A47c 27/ 08 U.S. Cl. 5-347 4 Claims ABSTRACT 0F THEDISCLOSURE A multiple cell, fluid pressure system utilizing a valvewhich substantially fills one set of cells before exhausting the otherset of cells whereby movement of a patient thereon is held to a minimumin a horizontal plane.

'This invention relates to a therapeutic mattress and pressure systemadapted to provide cycling alternate adjoining body support areas forthe user.

Persons required to lie in bed for an extended period of time suffer thediscomforts of general fatigue, muscular pains, and in some instances,decubitus ulcers or pressure sores. In order to relieve theseconditions, it has been proposed that multiple cell uid or airmattresses be employed with a pressure system to alternately shift thebody support pressure areas from one location to another. Although suchprior mattresses have reduced the discomforts of the user, they have notsatisfied the prerequisites required to adequately insure against tissuedegeneration nor have they provided efficient and relativelymaintenance-free operation during an extended period of usage.

It is known that certain bony parts of the body such as heels andshoulders are more prone to become sore during convalescence than otherparts of the body. Further, the area of these parts which contact themattress is relatively small compared to the size of the mattress cellsnormally used. Consequently, even though the adjoining cells arealternately inflated and deflated, the small body areas often remain xedin pressure point location upon lone cell width.

Accordingly, an object of this invention is to reduce the mattress cellwidth in those sections of the mattress which normally support the smallbony areas of the body to better assure a transfer of the support areasbetween adjoining cells.

It is also known that therapeutic mattresses employing cells having morethan one width dimension have been proposed. For instance, one suchmattress employs essentially bifurcated cell extensions of largerlongitudinal cells located at the bottom of the mattress. It has beenfound that such mattresses fail to combat tissue degeneration at severalof the small bony areas of the body mentioned above. Further, theseknown mattresses, because of their simplicity of cell layout and minimumseal joints, are relatively weak and therefore with not withstandextended usage. Also, such mattresses are not reversible, therebyhastening failure, and they additionally lack universality forpositioning purposes.

Accordingly, a further object of this invention is to provide greatercomfort for the user, and reversibility and universality of the mattressby employing smaller cells at prescribed locations on the mattress.

Another object of the invention is to make the mattress more rugged byfabricating the cells in at least three sections, the center sectioncells being larger in width than the outer section cells.

When a person is lying on an alternating pressure support mattress, somedisturbance occurs when the supported height of the body is changed.This has been evident in some prior mattress designs which allowed theuser 3,462,778 Patented Aug. 26, 1969 to move alternately from arelatively high position when one set of cells was fully inflated to arelatively low position whereat the adjoining cells were at an equallevel and pressure. Such cyclic vertical movement is bothersome to theuser.

Accordingly, a further object of the invention is to transfer the bodysupport areas from one cell to the adjacent one at a time when bothcells are substantially fully inflated to minimize vertical movement ofthe user.

A still further object of the invention is to provide an improvedtherapeutic mattress and iluid pressure system.

The foregoing objects are achieved in one aspect of the invention by theprovision of an inflatable mattress having at least three sections, eachof which includes two sets of interdigitated cells. The outer sectioncell sets utilize cells having a width substantially less than thecentral section cells. A fluid pressure system is connected to themattress to provide alternate inflation and deation movements of theadjoining interdigitated cells. This system operates in a manner tomaintain one set of cells in an inated position while the other set ofcells is deflated and then substantially inflated again. Accordingly,although the users pressure points on the mattress change position fromone cell to the adjoining cell during each cycle of operation, theactual transfer of the support areas occur without substantiallyaltering the support height of the user.

For a better understanding of the invention, reference is made to thefollowing description and accompanying drawings in which:

FIG. 1 is a plan view of the inatable mattress coupled to the pressuresystem;

FIG. 2 shows the manner in which the pressure system valve is mounted;

FIG. 3 is a view taken along line 3-3 of FIG. 2 of the stationary memberof the valve;

FIG. 4 is a view taken along line 4-4 of FIG. 2 showing the rotatingvalve member; and

FIG. 5 is a chart illustrating the operation of the valve in thepressure system as well as the inflation and dellation movements of theadjoining mattress cells.

Referring generally to FIG. l, mattress 11 is provided with two sets ofinterdigitated cells 13 and 15 formed by seal ribbons 17. Accessconnections 19 and 21 are attached to cell sets 13 and 15, respectively.Fluid pressure is supplied to mattress 11 from pump 23 through chamber25, conduits 27 and 29 and valve 31. The fluid pressure from the valveis transferred to the mattress by conduits 33 and 35. An adjustablepressure relief valve 24 is also connected to chamber 25 to insuremaintenance of proper pressure in the system.

More specifically, mattress 11 may be formed from two rectangular vinylchloride sheets of .020 inch thick plastic matterial having a peripheralcontour similar to a typical hospital bed mattress. The sheets areattached to one another by seal joints indicated by ribbons 17 aroundthe periphery. Similar seal ribbons form the separating fluid imperviousjoints between cell sets 13 and 15.

As indicated in FIG. 1, the mattress is formed with at least threedistinct sections 37, 39, and 41. The peripheral channels 43 andintermediate channels 45 serve to interconnect the respective cell sets13 and 15 so that a given cell set in each mattress section inflates anddeflates along with its counterpart in the other sections.

It is to be noted that access connections 19 and 21 may be disposed atboth ends of mattress 11. Also, the configurations of outer sections 37and 41 substantially conform to one another. Accordingly, such a layoutof cells and access connections provides reversibility for the mattress.Suitable plugs 48, clamps or other means may be employed to seal olf theconnections 19 and 21 which are not being used at the time.

The mattress is more rugged than previous ones for several reasons. Forinstance, the three mattress sections 37, 39 and 41 individually have alarge number of seal joints along ribbon 17 with few interconnectingribbon lines. Further, in areas where terminations or relatively sharpcorners would be encountered such as at the corners of the cell sets 13and 15 in central section 39, circular seal ribbons 47 are provided forstrength,

Central section 39 uses relatively wide cell widths for interdigitatedcell sets 13 and 15. Normally, such cells are arranged longitudinally tocontact the trunk portion of the patient. It has been found that cellwidths of about 1.75 inches are quite satisfactory for the centralsection cells.

The cells of sets 13 and 15 in the outer sections 37 and 41 generallyare positioned longitudinally of the mattress to reside where the rathersmall bony areas of the body rest. Two such areas are the heels andcertain parts of the shoulder. Due to the relatively small size of thesebony areas, it has been found beneficial to make the cells in outersections 37 and 41 substantially smaller than those in central section39. For example, cell widths for sets 13 and 15 in these outer sectionsmay have a width of about 1.00 inch. Accordingly, the adjoininginterdigitated cells are sufficiently small to transfer the pressuresupport point from one cell to the other even for the small bony partsof the body that they contact.

With respect to the fluid pressure system, pump 23 may be anyconventional air pump, preferably of the continuously operatingdiaphragm type capable of delivering about .75 p.s.i. Chamber 25, whichmay be made of plastic, serves as a pressure pulse damper and a noisesuppressor. The pressure relief valve preferably comprises a variablecontrol bleeder type valve.

Referring to FIGS. 2, 3, and 4, valve 31 employs a stationary member 51and a rotating member 53. These members have flat faces 55 and 57 whichare formed to mate in a substantially air tight manner. Members 51 and53 are molded from graphite so that there is little friction and a goodhermetic seal between faces 55 and 57.

The valve 31 is mounted on bracket 59 attached to the pressure systemchassis, not shown, by means of motor shaft 61 and spring 63. The shaftis driven by an electric clock motor 65 through a gear reductionmechanism 67. Rotating member 53 is affixed to shaft 61 by means of acotter pin 69 nesting in slot 71. Spring 63 presses against stationarymember 51 to assure that the flat faces 55 and 57 remain in intimatecontact. The shaft passes through member 51, which is held againstrotation by the conduit lines 27, 29, 33 and 35. It is to be noted thatvery little turning force is exerted on stationary member 51 duringrotation of member 53 because of the low friction.

During operation, the clock motor 65 runs continuously to drive shaft 61and rotating member 53, while stationary member 51 remains in fixedposition pressing against member 53 by action of spring 63. It has beenfound that 15 revolutions per hour of member 53 is satisfactory. Thisgives a cycle time of four minutes during which the cell sets 13 and 15in mattress 11 proceed through one alternation of inflation anddeflation by virtue of the full revolution of rotating member 53.

FIGURES 3 and 4 illustrate the details of valve 31. Stationary member 51has a central opening 73 through which the rotating shaft 61 passes.Oppositely disposed inlet ports 75 and 77 extend into the body of member57 and terminate in openings 79 and 8-1 respectively on the flat face55. These inlet ports are preferably located with centers lying on aninner concentric circle. Discharge ports 83 and 85, which are connectedto cell sets 13 and 15 through couplings 33 and 35, also extend into thebody of member 51 and terminate at openings 87 and 89 respectively onface 55. The discharge ports terminate at positions lying on an outerconcentric circle.

Accordingly, air is supplied to stationary member 55 through inlet ports75 and 77 and discharged to the mattress through ports 83 and 85.

The rotating member 53 of the valve has a central opening 91 for shaft61. This member is affixed to the shaft and rotates therewith by virtueof the nesting relationship of cotter pin 61 in slot 71.

The flat face 57 of rotating member 53 is provided with an arcuate airtransfer groove 93 and an arcuate air exhaust groove which has anopening 97 to the atmosphere. The arcuate length of groove 93 is lessthan of rotation by approximately the diameter of openings 87 and 89.The radial width encompasses both of these openings. The width andlength has to be suicient to straddle an inlet port opening and adischarge port opening to transfer the air to the mattress cells.However, the arcuate length preferably is less than that required tostraddle both discharge port openings 87 and 89 since there is no desireto connect the cell sets 13 and 15 to a common pressure source for aperiod of time sufiicient to cause the pressure in both cell sets toequalize. When this occurs, both cell heights drop and then one of themwill rise again to a fully inflated position. This up and down movementis disturbing to the patient.

Arcuate discharge groove 95 has a location and radial width such that itonly intercepts discharge port openings 87 and 89 in member 55 duringrotation. The length of groove 95 is sufficient to straddle onedischarge port at a time. When the groove is over one of the dischargeports, the mattress cell set connected at that port is dellated byexhausting to the atmosphere through opening 97.

Face 57 of member 53 is provided with lands 99 and 101 lying betweengrooves 93 and 95. During rotation, the arcuate lengths of these landsdetermine the hold period between the inflation and deflation cycles ofthe apparatus. Also, land 101, in conjunction with the speed of rotationand the pressure in the system, determines the length of time needed tohold an inflated cell set in that condition so that the other cell setcan be substantially inflated before the first set is exhausted. Asmentioned previously, this condition is desirable so that the patientdoes not sense any appreciable vertical movement on the mattress whilethe pressure support points on his body are being transferred betweenadjoining cells.

FIG. 5 will aid in an understanding of the operation of the inflationand deflation cycle of the mattress cells as well as the pressure systemvalve sequence. Presume that cell set 13 is deflated and cell set 15 isinflated and holding at the beginning of a cycle, and that rotatingmember 53 is moving counter clockwise approximately from the positionshown in FIG. 4. Arcuate groove 93 will first encounter opening 87 ofdischarge 83 and co'nnect it with inlet port 75. This causes the air tobe supplied to cell set 13 in the mattress 11. The cells of set 13proceed to inflate, and, approximately at the time they reach fullinflation, discharge arcuate groove 95 intercepts opening 89 of port 85.This causes cell set 15 to deflate by exhausting to atmosphere throughopening 97. During continued rotation of member 53, port 83 remainsconnected to the source of air pressure first through port 79 and thenport 77. At the same time, cell set 15 is being exhausted through groove95 and is finally held in that condition by land 99. At this point,member 53 has rotated about member 51 about 180 from the initial assumedstarting position. The alternate inflation-deflation sequence of themattress cells then begin. Grove 93 now moves over port S5 leading tothe deflated cell set 15 and begins to inflate these cells. At the sametime, land 101 is positioned over opening 87, thereby holding cell set13 in the inflated condition. This hold period may last for about 50degrees of rotation, after which exhaust groove 95 encounters portopening 87 to cell set 13 to begin exhausting. Here again, the timingbetween exhausting of cell set 13 and full inflation of cell set 15 issuch that the patient senses no up and down movement during transferupon the support cells. Some overlap of the iniiated hold period on onecell set with the full inflation period of the other set can betolerated by the patient. However, it is not desirable to shorten theinilated hold position to the extent that the other set is not near fullinflation since it will cause patient movement as pointed out above.

During the iinal rotational movement to complete the 360 cycle, groove93 remains in contact iirst with port 77 and then 75 to maintain cellset 15 inflated. During this same period, groove 95 is straddling port83 and land 99 to maintain cell set 13 in .a deated condition.

It can be readily understood from the above description that thisinvention provides an improved fluid pressure system and therapeuticmattress formed to produce cycling alternate adjoining body supportareas for the user. The mattress is rugged and formed for comfort,therapeutic value, reversibility and universality. Further, the pressuresystem is unique and eicient, and it relieves the patient from thediscomfort of vertical movement experienced with prior mattresses.

What is claimed is:

1. In a uid pressure system, the combination of an inflatable mattressformed to provide cycling alternate adjoining body support areas for theuser having at least rst and second sets of sealed fluid imperviousinterdigitated cells with an access connection for each cell set, acontinuously operating pump formed to provide fluid pressure, and avalve interconnecting said pump and said access connections foriniiating said cell sets, the valve comprising a stationary member and arotating member, the stationary member having inlet ports coupled to thepump and spaced discharge ports coupled to the access connections ofsaid mattress, each of said ports having an opening into a iiat faceformed on said stationary member, the rotating member having a lat faceformed to mate in a substantially Huid-tight relationship with the faceof said stationary member, said rotating member face being formed toprovide spaced arcuate grooves separated by lands, the arcuate groovesand lands being arranged to continuously block communication through thevalve ports between said Iirst and second cell sets, the rst of saidgrooves having an arcuate length sufficient to straddle an inlet anddischarge port, the second of said grooves having an exhaust opening toatmospheric pressure, the grooves and lands further being arrangedrelative to the stationary member ports during rotation to sequentiallymaintain each set of cells inflated while the other set is deflated andthen substantially inated to provide alternating support on adjoiningareas of the mattress without substantially altering the support heightof the user.

2. A system in accordance with claim 1 wherein the fluid pressure issuliicient to inflate a set of said cells through the valve in less thanhalf the degrees of movement of said rotating member during the periodwhen the first of said arcuate grooves is in communication with an inletand discharge port.

3. A system in accordance with claim 1 wherein a land separating thelirst and second grooves is of suicient arcuate length to maintain iiuidpressure in one of said cell sets until the second of said cell sets issubstantially inflated.

4. A system in accordance with claim 3 wherein the stationary valvemember has two oppositely disposed discharge ports terminating on anouter concentric circle and two oppositely disposed inlet portsterminating at positions arcuately positioned between said dischargeports on an inner concentric circle, the first groove of said rotatingmember having a radial width sufcient to encompass both said inlet anddischarge ports and the second of said grooves having a radial widthsufficient to encompass only said discharge ports.

References Cited UNITED STATES PATENTS 1,772,310 8/1930 Hart 5-9112,719,986 10/1955 Rand 5-348 3,199,124 `8/1965 Grant 5--349 3,388,7016/1968 Schreiber et al. 128-33 CASMIR A. NUNBERG, Primary ExaminerlANDREW M. CALVERT, Assistant Examiner U.S. Cl. X.R. 128-33

